Menus that are near the right-hand side of the screen end up being

positioned too far to the right. This is easily seen with the Follow

menu. The logic was incorrect in its calculations, and ended up off by

the difference between the window width and the right edge of the handle

element.
It now attempts to more carefully place this on the screen without

scrolling off the side. First, it tries to right-align it to the parent

handle. If that's still off the side, then it tries to align it to the

right-most pixel of the window. And then, if we're off the left-hand

side, it tries to align to the left-most pixel of the window.

Tested with some menus across the width of the page. Verified this

fixed an issue I encountered with a menu on the right-hand side. It

appeared properly aligned.
Forced some bad positions to trigger the different scenarios and

verified the menu positions were correct.